##Infrared compositing## If you have [near-infrared imagery](/tool/near-infrared-camera) you can composite that imagery with the visible-light imagery to see how healthy the vegetation is. * [NDVI and NRG compositing](/wiki/ndvi) * [Video: Creating infrared composites of aerial wetlands imagery](https://www.youtube.com/watch?feature=player_embedded&v=pv6xB0y-rX4) - Learn to combine infrared and visible-light photographs (taken from balloon photography) to produce an "NRG" composite, where reddish color indicates photosynthesis. * [Video: Creating false-color NDVI with aerial wetlands imagery](https://www.youtube.com/watch?v=-nNnWEHNO_w) - Learn to use the open-source GIMP application to create a Normalized Differential Vegetation Index image from infrared and visible-light aerial photographs. Also explore false-color techniques for presenting the data. ##Contrast adjustments## Stretch the contrast and saturation of your images to see more detail, especially underwater. Read more here: * http://publiclaboratory.org/notes/warren/10-25-2011/using-colorcontrast-enhancement-see-water-aerial-photos ###Decorrelation stretching### _Nathan Craig writes:_ Decorrelation stretching may be a method to consider. Various flavors of the transformation are easily run using the DStretch Plugin for Image J. Several that seemed to represent variability relevant to the case study are included. I use DStretch to help bring out detail in rock art scenes that are highly eroded. However, the method has utility outside of rock art studies. It may be an additional approach to consider when trying to identify pollution or other contaminants. Here is information on DStretch http://www.dstretch.com/ Here is a paper that describes the transformation http://eospso.gsfc.nasa.gov/eos_homepage/for_scientists/atbd/docs/ASTER/atbd-ast-06.pdf [Browse more of these](https://www.flickr.com/photos/publiclaboratory/sets/72157627992773600/detail/) ##Classification## Using the ratios of Red, Green, and Blue (and possibly Near-infrared), spectral classification attempts to categorize regions of an image by land type. ###Read more on the [classification page »](/wiki/classification)### ### Image Analysis [activities:image-analysis]...
| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| warren | "Hi! Just re-reading, is it right that the image analysis produces (as it's complete output): perimeter of each particle area of each particle ..." | Read more » | almost 8 years ago | |||
| warren | "Hi! Is Simon's macro still at the URL listed above? Or is there a more up-to-date version, potentially open sourced? Thanks! " | Read more » | almost 8 years ago | |||
| mathew | "Followup on automating this process https://publiclab.org/notes/SimonPyle/05-13-2016/automating-imagej-for-particle-image-analysis " | Read more » | over 8 years ago | |||
| mathew | "Although we are hopeful that Simon's strategies listed here can get us to a particle count, If they aren't sufficient Rongjun Qin recommended we lo..." | Read more » | over 8 years ago | |||
| mathew | "You can get the analysis spreadsheet here: https://docs.google.com/spreadsheets/d/1xSVT9lxary0zZhhEqhrX3hsdIb4shbYhaOJx_RWhESg/edit#gid=0 " | Read more » | over 8 years ago | |||
| mathew | "That's a great writeup! thanks Simon. If anyone needs an image set to play with, please e-mail me, and I can share the files. They're too large t..." | Read more » | over 8 years ago | |||
| mathew | "Also see @Damarquis's note on using MaxEntropy https://publiclab.org/notes/Damarquis/10-20-2015/using-imagej-to-analyze-threshold-and-saving-result..." | Read more » | over 8 years ago | |||
| mathew | "I'm working on creating a spreadsheet out of these equations. @Marlokeno it looks like I'm going to use Sutherland's gas law along with average te..." | Read more » | about 9 years ago | |||
| mathew | "excellent suggestion, thanks for pulling that up! On a brief review, it confirms our experience that PM10 is probably the smallest size we can rel..." | Read more » | about 9 years ago | |||
| acenchase | "This is very interesting. May I suggest checking out the guide published by NIST which has some guidelines for performing image analysis by SEM in..." | Read more » | about 9 years ago | |||
| mathew | "@Damarquis has notes on using ImageJ in windows and on thresholding: http://publiclab.org/notes/Damarquis/10-20-2015/using-imagej-to-analyze-thresh..." | Read more » | about 9 years ago | |||
| marlokeno | "It is possible the wikipedia article on Reynolds numbers might help- https://en.wikipedia.org/wiki/Reynolds_number At any rate, the article does g..." | Read more » | about 9 years ago | |||
| marlokeno | "There is an article in "Aeolian Research", Dec. 2014, entitled "The size distribution of desert dust aerosols and its impact on the Earth system." ..." | Read more » | about 9 years ago | |||
| liz | "true - images of melting ice was used by community members as "thermal clues" when searching for unknown/undocumented inflows into the canal. " | Read more » | over 9 years ago | |||
| warren | "There may have been confusion in part because some of the winter images GLAM took show trails where inflows melted ice, whether due to the flow of ..." | Read more » | over 9 years ago | |||
| gretchengehrke | "Ecta64, that's a good point. Liz confirmed that they never used thermal imaging system on the Gowanus, so it must have been a miscommunication abo..." | Read more » | over 9 years ago | |||
| gretchengehrke | "Hi Chris, Edan, whom I interviewed for this, was pretty adamant that the photos he saw and used were thermal images. I know specific kinds of came..." | Read more » | over 9 years ago | |||
| cfastie | "Gretchen, It's not just these particular photos, the Public Lab infrared cameras do not record thermal information. They are all near infrared came..." | Read more » | over 9 years ago | |||
| gretchengehrke | "Hi Chris, Thanks for the note! Good point -- I did not link to a thermal image there, nor use one for the lead image. I will sort through MapKnit..." | Read more » | over 9 years ago | |||
| cfastie | "Hi Gretchen, The Public Lab infrared images you refer to here are not thermal images. The near infrared photos don't have any information about tem..." | Read more » | over 9 years ago | |||
| jholmes5 | "It would be nice to have a scale. At the Open Hours last week they did say it was hard to get absolute temperatures without some sort of calibratio..." | Read more » | over 10 years ago | |||
| jholmes5 | "It seems like the red is cooler, since the beaches and shallow water of Jamaica Bay are that lighter yellow color, and they should be warm spots. ..." | Read more » | over 10 years ago | |||
| nicholas | "Yes I should have documented my work a bit better. I basically followed the tutorial and then kept moving the zoom around and playing with the set..." | Read more » | over 10 years ago | |||
| nedhorning | "I'm not sure what would cause that red spot. There isn't a legend or an image date so I'm assuming that the red spot is cooler than the surrounding..." | Read more » | over 10 years ago |